At least 300 people have been killed in a massive fire at a prison in central Honduras, and the toll is expected to rise, officials say.

Soldiers, police and anxious relatives surrounded the prison in Comayagua, about 75km north of the capital, Tegucigulpa, on Wednesday morning. Television images showed weeping relatives pressed against a chain link fence as they waited for news.

The blaze, which broke out late on Tuesday, was one of the worst prison fires ever in Latin America, and local radio reports said many of the inmates were burned to death inside their cells.

"We are pulling out bodies," Danilo Orellana, head of the prison system, said.

"The situation is serious. Most have suffocated."

'Hellish' scenes

Danelia Ferrera, a senior official at the attorney general's office, said: "It is estimated that there are 357 dead."

Earlier Lucy Marder, head of forensic services in Comayagua, said in a radio news conference that 272 people had been killed, adding: "This is a preliminary report, there could be a lot more deaths."

Josue Garcia, the Comayagua fire department spokesman, said he saw "hellish" scenes while trying to put out the fire, with many prisoners "burned to death or suffocated in their cells".

Witnesses said some of the inmates escaped the blaze by jumping from the prison rooftop, and there were reports that some of them had fled the facility and were on the loose.

Officials are still investigating the cause of the fire.

Local firemen said they were prevented from entering the prison due to shooting.

However, Orellana said the fire did not appear to have been caused by a riot and that investigators were looking into whether it was caused by an inmate or by a short circuit.

"We have two hypotheses," he said. "One is that a prisoner set fire to a mattress and the other one is that there was a short circuit in the electrical system."

Honduras has the highest murder rate in the world, recording more than 80 homicides per 100,000 people in 2009, a rate 16 times that of the US, according to a UN report last year.

Frequent riots

There are frequent riots and clashes between members of rival street gangs in its overcrowded prisons

The gangs, known as "maras", started in the US and then spread down into Central America, with members covered in distinctive tattoos and involved in drug trafficking, armed robbery and protection rackets.

Honduras is also a major drug-trafficking transit point for South American cocaine moving north to consumers in the US, and authorities say there is increasing presence of violent Mexican drug cartels in the country.

Across Honduras, prisons are filled to double their capacity. The facility in Comayagua housed more than 800 inmates - well above its capacity.

More than 100 prisoners were killed in a fire in the textile manufacturing town of San Pedro Sula several years ago.